1. Field of the Invention
This invention pertains to implants for use in intraluminal applications. More particularly, this invention pertains to stents for use in vascular applications.
2. Description of the Prior Art
Stents are widely used for supporting a lumen structure in a patient's body. For example, stents may be used to maintain patency of a coronary artery, other blood vessel or other body lumen.
Commonly, stents are metal, tubular structures. Stents are passed through the body lumen in a collapsed state. At the point of an obstruction or other deployment site in a body lumen, the stent is expanded to an expanded diameter to support the lumen at the deployment site.
In certain designs, stents are open-celled tubes that are expanded by inflatable balloons at the deployment site. This type of stent is often referred to as a “balloon expandable” stent and is often made of a plastically deformable material such as stainless steel. Other stents are so-called “self-expanding” stents. Self-expanding stents do not use balloons to cause the expansion of the stent. An example of a self-expanding stent is a tube (e.g., a coil tube or an open-cell tube) made of an elastically deformable material. Elastically deformable self-expanding stents are typically secured to a stent delivery device under tension in a collapsed state. At the deployment site, the stent is released so that internal tension within the stent causes the steal to self-expand to its enlarged diameter. This type of stent is often made of a “super-elastic” material such as nitinol. Other self-expanding stents are made of so-called shape-memory metals. Such shape-memory stents experience a phase change at the elevated temperature of the human body. The phase change results in expansion from a collapsed state to an enlarged state.